The present invention relates a method and an apparatus to affix longitudinally an elastic band pair onto a moving web as a primary component of continuous article along opposite sides of a said web so that said elastic band pair may be disposed on the web at least partially in a non-parallel relationship to each other.
The present invention is applicable to the production of disposable articles placed on the crotch area of the human body and provided with elastic band to assure fitness around the legs, for example, a diaper, diaper cover or training pants for babies, to thereby affix said elastic bands onto such article on opposite sides of the crotch area in a diagonal, curved or non-parallel disposition.
To obtain the desired fitness around the legs of user and thereby to minimize possible leakage of excretions, for example, in a disposable diaper or pants, there have already been proposed methods and the apparatuses for affixing the elastic band onto such article on opposite sides of the crotch area in a diagonal or curved, i.e., non-parallel disposition.
In such prior art, the inventive concepts have been often involved into the means to feed the elastic band to a moving web as the primary component of the continuous article and to affix this elastic band onto the web.
However, to construct said means so that the elastic band can be affixed onto the web in a non-parallel disposition, for example, diagonal or curved disposition, the mechanism of such means is necessarily complicated and it is difficult for such a complicated mechanism to be continuously operated at a high speed so that the elastic band may be affixed, through the entire length of the web, at predetermined positions in orderly and uniform manner. In view of such difficulties, the elastic band has usually been affixed onto the disposable diaper at opposite sides of the crotch area, regardless of the teachings of prior art. It will be readily appreciated that diaper provided with the elastic band in such a parallel disposition can not provide satisfactory fitness around the legs of user. This not only deteriorates appearance and feeling but also may permit leakage of excretions.
The object of this invention is to overcome the problems as set forth above with a relatively simple method and apparatus.